You must be able to concentrate your mind on one object for five minutes.

I could not concentrate my mind upon the papers in front of me.

There was one way he knew to concentrate his mind for the solution of a problem.

How can a man concentrate his mind with all this noise?

This will concentrate their minds and make sure they do what is right.

Personal liability, in other words, can concentrate a director's mind.

Now look again; choose a single image, and concentrate your mind on that.

He tried to concentrate his mind on some one definite thing.

He turned away from the forest and sought to concentrate his mind upon other things.

We should be quiet and concentrate our minds to understand.